1. Field of the Invention
The invention relates to a metal substrate, more particularly, the invention relates to a structure of a heat dissipation substrate adopted in a heating device and a fabricating process of the same.
2. Description of Related Art
With the progression in fabricating technology, light emitting diodes (LEDs) have gradually increased the light emitting efficiency through persistent research and improvement to further enhance the light emitting brightness thereof so as to satisfy demands in various products. In other words, other than improving the external packaging thereof, LEDs also require advanced design to achieve higher electrical power and working current, which would lead to the fabrication of LEDs with high brightness. However, when the electrical power and the working current of LEDs are increased, LEDs generate higher thermal energy which then affects the performance of LEDs or results in the malfunction of LEDs by overheat.
Conventionally, a copper substrate is adopted in a heat dissipation substrate for an etching process, so that a plurality of recesses is formed on an upper surface of the copper substrate. Thereafter, an insulating material is provided to fill the recesses, where the insulating material substantially aligns with the upper surface of the copper substrate. A copper layer is then electroplated on the upper surface of the copper substrate and the insulating material. A patterning process is performed to the copper layer to form a patterned copper layer. Finally, a plurality of independent heat dissipation substrates is formed through a singulation process to complete the fabrication of the heat dissipation substrates.
In general, when conventional heat dissipation substrate has a thickness more than 1 millimeter (mm), structures of individual heat dissipation substrates can be formed rapidly by punching as the larger heat dissipation substrate has sufficient flexural strength. Obviously, structures of individual heat dissipation substrates can also be formed through etching in the fabrication of conventional heat dissipation substrate. Since the etching process requires an additional photo-resist layer covering on the copper substrate and the copper layer of the insulating material, additional steps and fabrication cost are needed. Moreover, when the thickness of the heat dissipation substrate is reduced in half to satisfy the trend of miniaturization in packaging technology so that the thickness of the heat dissipation substrate is decreased from 1 mm to less than 0.6 mm, the heat dissipation substrate easily bends and deforms due to insufficient flexural strength, thereby affecting the subsequent packaging process.